MySQL stored procedure to generate "safe noise"

I'm playing around with stored procedures, and thought I'd try my hand at creating a function used in various capacities at work. Here it is.

USE test;
DROP FUNCTION IF EXISTS safe_noise;
DELIMITER $$
CREATE FUNCTION safe_noise (n INT UNSIGNED)
   RETURNS VARCHAR(100) NOT DETERMINISTIC
BEGIN
   DECLARE x CHAR(100) DEFAULT
      "bcdfghkmnpqrstvwxzBCDFGHKMNPQRSTVWXZ23456789";
   DECLARE y CHAR(100) DEFAULT "";
   DECLARE i INT;
   WHILE n > 0 DO
      SET n = n - 1;
      SET i = 1 + FLOOR(44 * RAND());
      SET y = CONCAT(y, SUBSTR(x, i, 1));
   END WHILE;
   RETURN y;
END
$$
DELIMITER ;

-- Sample output:
--    mysql> select safe_noise(50);
--    +----------------------------------------------------+
--    | safe_noise(50)                                     |
--    +----------------------------------------------------+
--    | 96Pw5CKDPW4g5pv984DSdp4VfpXvtK3KpDR6KfSp9tHVkFbKXp |
--    +----------------------------------------------------+
--    1 row in set (0.01 sec)

Aside: I'm really surprised that blogger.com can't handle verbatim text excerpts. There's more to life than chin music, people! God forbid I should post some Python...